39 



studied, only one kind of trichomes was present. Care was taken 



to examine specimens of each species collected in various localities. 



It is quite likely that there are species in which the hairs are 



more or less intermediate in form between the two kinds here 



Figs, i- 



Hairs of Astragalus. 



described. In fact in A. Caroliniamts some of the hairs have the 

 short "arm" quite short, so that instead of being nearly the 

 length of the longer arm, it is only about one sixth of the 

 length. The hairs shown in Fig. 2 are of about average form 

 for the species. 



Since the two kinds of hairs seem to be characteristic for the 

 particular species, it is possible they could be made use of by 

 systematists. The great difficulty of the genus Astragalus is 



